Dangers of infection and cross-infection, much high-lighted by the spread of AIDS, mean there is a need for hollow-needle devices as drugs etc applicators with automatic retraction and designed for single use only, i.e. designedly not lending themselves to re-use. This is, perhaps, particularly the case for cartridged drugs etc supplied as a one-dose item complete with applicator. Indeed, there have been many proposals over the years for such applicators, especially recently, but most are of doubtful practicality or of complex and costly construction, even both. We have, ourselves, made basic proposals (PCT application GB92/00652) for practical and low-cost single use hypodermic syringes (and body-fluid samplers) with automatic needle retraction on release of integral internal latching of an outer body part for a needle holder, including usable with cartridged drugs etc by use of a plunger element to release the needle holder latching after cartridge discharge.
We have made further proposals (PCT application no GB93/01004) for preloaded cartridged drugs etc applicators affording automatic needle retraction, including self-powering provisions for automatic needle extension before discharge of cartridge contents and needle retraction, and having deflectable angled piston rod arms for temporary drive stroke latching and then release deflection by cartridge engagement.